


Equivalent Exchange

by alexiel_neesan



Category: Teen Wolf (TV)
Genre: Alternate Universe - Fusion, Blood, Episode AU: s01e04 Magic Bullet, Episode Related, Fullmetal Alchemist fusion, Gore, Hurt Derek, Other, Wolfsbane Poisoning, graphic description of amputation
Language: English
Status: Completed
Published: 2014-09-24
Updated: 2014-09-24
Packaged: 2018-02-18 14:29:58
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 2,148
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2351729
Author URL: https://archiveofourown.org/users/alexiel_neesan/pseuds/alexiel_neesan
Summary: <blockquote class="userstuff">
              <p>Taking Derek to Deaton's automail shop after he was shot with a wolfsbane bullet went bad, very bad.</p>
            </blockquote>





	Equivalent Exchange

**Author's Note:**

> If I repeat it often enough, it'll work and I'll never write more in that sorta fusion verse of Teen Wolf and Fullmetal Alchemist. 
> 
> Thus, enjoy this piece, cast to your reading pleasure.
> 
> Title unashamedly stolen from Fullmetal Alchemist. Questions, comments and other things related to Teen Wolf, [the Cheeseverse tumblr](http://cheeseverse.tumblr.com/) awaits.
> 
> Inspired by [Torakodragon's excellent art](http://torakodragon.tumblr.com/tagged/automail!derek) and endless rewatches of FMA Brotherhood.

  
  
When the door of the shop opened again, Scott brought the bullet, and Deaton.  
  
Derek tensed, about to move, but Deaton was faster. There was a piece of wood in his hand, and Scott and Stiles watched Derek failing to grab it, incomprehensibly. After that, which only took a few seconds, Derek let Deaton closer.  
  
“The bullet is not going to be enough,” said Deaton, examining Derek’s arm. The fingers of the hand were turning blue and black and crooked now, the nails peeling off. Black liquid was spattering from Derek’s mouth to the table he was hunched over, panting and choking. He was unable to stay upright even with the table and Stiles’ assistance. Stiles wanted to throw up, more than ever. Scott was watching, horrified.  
  
“Derek,” Deaton said, the lights glinting off the work table and automail parts and instruments around them. “I cannot save your arm. But I can save you.”  
  
“Do… what you have to do,” said Derek. Or something close enough that Deaton took it as agreement.  
  
Deaton calmly but urgently listed necessities for Scott to bring to him, starting the preparation ritual that Stiles had never witnessed before.  
  
“Mr. Stilinski,” Deaton said, and Stiles jumped, hand clenched around Derek’s good wrist, and surprised that Derek had let him hold on. “Please assist us.”  
  
That was how Stiles witnessed and helped with his first automail surgery. There was no time to sterilize the room or change clothes— Deaton pointed him to the work aprons, made him help Derek lie on the table, help put a basic IV in.  
  
He saw how Scott and Deaton pushed the burning wolfsbane in to stop the spread of the rot and held onto the convulsing man, how they cut the skin of the shoulder away to reveal bone gone dark and brittle, the removal of flesh and bone —Stiles had to turn away then—, the sound of aspired blood, the glimpsed opened skin of the ribcage to replace scapula and rib and collarbone with automail-bearing metallic “bones”, the slick wet sound of metal inside a body.  
  
Thorough, Stiles breathed slowly, pushing through the sight of blood and its overwhelming smell. Thorough, Stiles was in awe of Scott and his boss, their absolute calm. Thorough, Stiles kept his hands on Derek, pushing the sweat-soaked hair away from his face again and again, giving him something else to focus on as per Deaton’s instructions. Derek’s other hand griped the edge of the table, so hard it groaned, left dents.  
  
There were no painkillers, no anesthetics— not in the quantities and qualities Derek as a werewolf would be needing to work properly, had said Deaton. Derek never closed his eyes, gone glassy and blank, staring at the ceiling. His teeth had gone through the teeth guard in the first ten minutes.  
  
Stiles tried not to look. He saw Derek’s arm, nail-less and black and starting to shrivel, being joined by rotted bones on a side table, the blood surrounding them black and red.  
  
Stiles, multiple times in the past, had expressed his enthusiasm for automail surgeries. The gore and blood and, in his mind, glory coming from needing one, as most people he had meet with one or more were soldiers and firefighters and the like, attracted him, typical teenager that he was. He found the engineering of the automails themselves fascinating, the differences in design, the trends and bells and whistles one could add to limbs.  
  
Scott liked the actual maintenance, and was good at it, at the minutiae of moving parts. He had been Deaton’s apprentice for just a year, but could see going into that field. An automail mechanic was a good solid job, one that helped people. He had seen the difference having one or not made in someone’s life. But by working at Deaton’s, while the man was certified for it according to the diplomas in the entrance office, Scott never had had to entirely install an automail. Never had had to take limbs off, to see the blood and the tremor of the body underneath fighting for its life.  
  
The reality of automail surgery…  
  
Stiles found himself crying. He refused to think of hospital and dying people. He found himself whispering over and over that it’d be okay, it’d be over soon, he —Derek— was doing so well. Would be good, would be great, would be okay.  
  
Scott had to block the smell of blood, of pain, of fear. He had to block hearing Derek’s heartbeat, and Stiles’. He went into tunnel vision, following only Deaton’s instructions, a mantra of “Allison, Allison” running through his head to keep his heart beating steadily, to keep his hands from shaking, to keep himself anchored.  
  
By the time they were as far done as they could be, it was long past the middle of the night. Stiles felt light-headed from exhaustion, couldn’t understand how Deaton and Scott were still upright, how Derek’s eyes were still half-open and his heart still beating.  
  
Deaton fixed a small round canister to the shoulder port with a click, then straightened, sighing deeply. Scott mirrored him. There were splashes of blood on both of their aprons and clothes.  
  
“The implementation of the new limb will have to wait until everything heals suitably,” Deaton said, and when Stiles cranked his neck up to see, the arm socket was empty, glinting dully under the harsh glare of the workroom. The flesh surrounding it was red and white and stitched with black. “In the meantime, this,” and he pointed at the canister he had just installed, “will have to stay in. It’s delivering controlled doses of antidote for the wolfsbane’s poisoning.”  
  
Scott sat down on the nearest chair, almost falling over.  
  
“Now,” Deaton said, “Derek needs to rest, with supervision. He can’t stay here.”  
  
Both teens immediately started talking. “He can’t go with us—“ “We’re done with him!”  
  
Scott straightened from the slouch he had fallen in, and felt his eyes flare. “He’s been following me, and threatening me! Okay, we saved his life—“ He pointed at Derek on the table, his eyes now closed, chest moving shallowly up and down, “which means he’s gonna leave us alone. And if he doesn't, I'm gonna go back to Allison's dad, and I'm gonna tell him everything—“  
  
“You're gonna trust them? You think they can help you?”  
  
Derek’s voice was barely loud enough for Stiles to hear it over his own heartbeat, but it was loud enough to startle him. His eyes were open again, glazed with pain.  
  
Stiles and Scott had shot zombies in video games with more colors in their faces.  
  
“Well, why not? They're a lot freaking nicer than you are,” Scott spat.  
  
Stiles wanted to leave. He wanted to forget the night, forget werewolves, to take Scott and leave and hide away in his room. The… exchange going on at the moment was not going to go anywhere good.    
  
Derek struggled to sit up, panting harshly in the silent room. He visibly steeled himself before looking at his left shoulder, and the emptiness there. His jaw clenched. He turned his left side toward Scott, right hand shaking to keep himself up.  
  
“Is this not enough to show you exactly how nice they are?” The words were gritted out. “What do you think they’ll do to you when they find out what you are? Will they shoot you in the arm? Or just straight between the eyes?”  
  
“Okay, enough with the impending threats here—“ Stiles started, reaching to hold Derek’s arm and stabilize him.  
  
Derek didn’t react only because Deaton —who they had all seemed to forget was there too, and who knew about werewolves, that too— spoke out. “Am I right in assuming that by saying ‘Allison’s dad’ you were refereeing to Chris Argent, Scott?”  
  
It caught everyone by surprise.  
  
“Uh, yes,” said Scott.  
  
“You’d do well in staying a reasonable distance away from the Argent family, Scott.” Deaton calmly laid out the instruments they had used on the back counter, ready to be cleaned and put away. “They are notorious hunters of the supernatural— organized, ruthless, and willing to take down anyone who they deem a threat.”  
  
“They’re hypocrites and liars, they hide behind codes and rules to justify murder. They say they'll only kill an adult, and only with absolute proof. It’s a lie,” said Derek.  
  
Stiles gasped, points suddenly connecting. “The fire— your house, were they—“  
  
Derek nodded, went paler, stopped moving.  
  
Scott scowled, “What makes you so sure that they set the fire?”  
  
“’Cause they're the only ones that knew about us.”  
  
“Well, then they had a reason,” said Scott.  
  
“Like what? You tell me what justifies burning a family, burning kids to death. You tell me what justifies this,” and on this, Derek’s foot shot out, jabbing the side table where his arm and bones were resting, rattling it hard enough to make the limb move. A nail detached completely, and the visible head of the humerus crumbled to dust.  
  
“Oh god,” said Stiles, and he turned away, both hands clamped on his mouth to keep from throwing up.  
  
“That’ll be quite enough,” said Deaton. “I can write a note excusing you and Stiles from your first classes, but you can’t stay here much longer, I’m afraid.”  
  
“He’s not coming with me,” said Scott, staring at Derek and dismissing him entirely. He turned to Deaton, “What— How do you know about all this anyway?”  
  
Derek hunched on himself as if to present a smaller target, was looking at Deaton too, thinking hard. “… the advisor— you’re the keeper of balance, aren’t you?”  
  
Deaton came back to the side of the table, pulling gauze across Derek’s torso and stitches. The material went immediately red at the edge between flesh and metal.  
  
“I’m just an automail mechanic— keep the stitches dry and do not scratch at anything. Come back to see me in a week. We’ll talk measurements then.”  
  
“We’re done, come on Stiles,” said Scott.  
  
Stiles, still turned away to try not to throw up, waves a hand at Scott. “In a minute, bro. I got questions.”  
  
Scott scowled, glared at Derek who was hunched over sitting on the table and looking at nothing, took the note Deaton gave him and left.  
  
“You should go home, Stiles. It’s been a long night,” said Deaton. He didn’t seem inclined to answer any questions Stiles would have had if he was still running at 100%.  
  
“Yeah. Yeah,” Stiles said, absently. He turned carefully, not wanting to see cut arm and bones again. He knew he’d have nightmares about that.  
  
The side table was empty. He sighed.  
  
Derek was curled on himself on the table, head resting on his knees, and his hand pressing right at the edge of the bandages.  
  
Stiles took his apron off, put it behind him haphazardly. He then took a breath, held it in, pushed it out. His eyes hadn’t left Derek’s form.  
  
“You’re coming with me,” he said.  
  
Derek didn’t move.  
  
Stiles took off his jacket, held it out until the fabric brushed Derek. Derek opened his eyes, staring at the piece of clothing without seeing it.  
  
“You’re coming with me,” Stiles repeated, and he waited for Derek to get on with the program.  
  
Derek followed Stiles out, jacket draped over his upper body. No-one said anything more to Deaton. Stiles grabbed the note on his way out.  
  
Getting into the Jeep took a bit of time, as did walking to it, but Derek seemed stable enough on his own. Stable and silent, and he didn’t talk until the Jeep stopped in front of Stiles’ house.  
  
“What’re you doin’?” said Derek. He was slumped against the door and window. If he hadn’t spoken, Stiles would have thought he had passed out. Hoped that he had passed out.  
  
“Taking a chance,” Stiles said.  
  
“You wanted t’leave me for dead on the side o’the road this afternoon.”  
  
“Listen, there’s exactly three people I give a shit about. Your continued survival’s necessary for one of them to not get his ass killed. Ergo, I’m not interested in seeing you dead. Got it?”  
  
Derek seemed to relax at that. Which was the cherry of insanity on the insanity cake of a day it had been. Or it was just the fault of the bad lightning from the automated light over the garage, the one Stiles’ dad had asked him to replace three times in the last month.  
  
“My dad’s not in right now. And Deaton said you need rest with supervision. Unless you want to go back to your house in the woods?”  
  
“No,” replied Derek. His hand was holding Stiles’ jacket closed tight, and even in the bad light, there was no mistaking the shadows for another arm. “Hunters’re out. ‘d finish the job.”  
  
That was the cherry of outright chaos, Stiles decided, helping Derek to walk into his house.  
  
  
  
  
  
  
  
  



End file.
